/Engine/Source/Runtime/Engine/Classes/Animation/AnimCompress.h
Common compression utility to retain only intermittent animation keys. For example, calling with an Interval of 3 would keep every third key in the set and discard the rest
static void FilterIntermittentKeys ( [TArray](API\Runtime\Core\Containers\TArray)< struct [FTranslationTrack](API\Runtime\Engine\Animation\FTranslationTrack) > & PositionTracks, [TArray](API\Runtime\Core\Containers\TArray)< struct [FRotationTrack](API\Runtime\Engine\Animation\FRotationTrack) > & RotationTracks, int32 StartIndex, int32 Interval )